Problem: $3c - 10d - 7e - 2 = d - 2e - 9$ Solve for $c$.
Answer: Combine constant terms on the right. $3c - 10d - 7e - {2} = d - 2e - {9}$ $3c - 10d - 7e = d - 2e - {7}$ Combine $e$ terms on the right. $3c - 10d - {7e} = d - {2e} - 7$ $3c - 10d = d + {5e} - 7$ Combine $d$ terms on the right. $3c - {10d} = {d} + 5e - 7$ $3c = {11d} + 5e - 7$ Isolate $c$ ${3}c = 11d + 5e - 7$ $c = \dfrac{ 11d + 5e - 7 }{ {3} }$